Bulletin 229, Diseases of Citrus in Florida


 CONTROL OF FOOT ROT
 There are two general methods for the control of foot rot,
namely preventive safeguards in connection with the main-
tenance of the grove, and remedial measures after the trouble
occurs. The most effective way of avoiding foot rot is the use
of resistant rootstocks for budding in cases where these stocks
can be used to advantage, provided the trees are not budded too
low. Additional methods of prevention comprise the selection of
well-drained land or providing adequate drainage before plant-
ing, and the avoidance of too close planting, too low budding,
too deep setting, allowing the soil about the bases of the trees
to become too wet in irrigation, scarring the roots and bases
of the trunks in cultivation or in the old practice of cattle-pen-
ning, and the piling of dirt, wood, weeds, or trash about the
bases of the trees for any great length of time. The Porto Rican
practice of planting trees on mounds so that the crown roots
eventually become exposed above the surface of the soil as it
levels down should prove valuable in Florida for the prevention
of foot rot on sweet seedling orange trees and trees on this
and other susceptible rootstocks. This practice requires that
the mounds be kept free from weeds and mulched to maintain
the supply of soil moisture while the trees are young. It also
requires that implements of cultivation be kept away from the
bases of the trees and that close weeding be done by hand as the
trees become older, not to injure the roots.
 In the treatment of trees attacked by foot rot, since the disease
 occurs chiefly on the root-crown and the adjoining part of the
 crown roots and taproots, it is first necessary to clear away
 the top soil in a radius of about 3 feet around the tree in order
 to determine fully the extent of the trouble under the ground
 (Fig. 19). This should be done carefully so as not to scar the
 roots. Where a large number of trees are to be treated, this
 tedious job can be done to best advantage by washing the soil
 away with water, using one of the leads of hose from a power
 spraying outfit after disconnecting the spray nozzle or else re-
 placing the regular disk by one with a large hole. If the dis-
 ease is found to have developed so extensively as to practically
 girdle the tree it is useless to attempt to treat it by surgical
 methods. When the disease has not advanced too far, it should
 be treated by cutting out all areas of diseased bark, using a
 sharp knife, chisel, or gouge, as may be necessary. All dead